“O.P.Judd, the local Buick distributor has just received a letter telling of another triumph for the car that he represents. The letter describes fully the winning car and the cup of the Grand Duke Michael Alexandrovitch, which the Buick car easily walked away with in the race of 1912.The cup is gold and weights 2780 pennyweights. It is 25 inches high and 32 inches in circumference. The Buick was the only one of the contestants to finish with a perfect score in the fifteen days’ grind, winning the hill climb and speed contest, which is the most notable winning ever made in the foreign land. The driver, Petit, is a Texas boy now in Europe.”

Which event was this? Given that Grand Duke Michael Alexandrovitch was part of the Russian Imperial family, I guess that this event was in Russia. And was Petit really Henry Petit, who competed at Galveston, TX, in 1910 for Buick? (and the same H.Petit who competed with a Bedford at Brooklands in 1911?)

In 1912 the Cup of Grand Duke Mikhail Alexandrovitch won Petit (I don't know his first name) on Bedford car in the Rally for Emperor’s Prize (St. Petersburg - Riga - Warsaw - Kiev - Moscow), which was held on 30 June - 16 July (17 june - 3 July according old russian calender.
Another driver Drensfield on Buick retired before Warsaw.